why do all chemistry tests (especially testing for acidity or alkalinity) require distilled water and not tap water? and why do many tests use dry reagents (like dissolving solid citric acid in water) instead of liquid form?
2007-03-23 21:51:39 · 5 answers · asked by blubbablub 1 in Science & Mathematics ➔ Chemistry
Tap water contains a lot of dissolved minerals which could confuse certain tests. It will not particularly upset tests involving pH measurements because tap water is usually less acidic than distilled water. However, certain reagents start to decompose, ie get hydrolysed or oxidised, when dissolved in water, which is why they must be made up fresh.
2007-03-23 21:59:17 · answer #1 · answered by Gervald F 7 · 1⤊ 0⤋
to make it very simple, distilled water is a pure water, and pure water is the ideal type of solvent that is used in the laboratory, tap water contains dissolved minerals that could counteract with other reagents and affect the results of a certain tests.
2007-03-24 05:08:49 · answer #2 · answered by biancah V 1 · 0⤊ 0⤋
Tap water contains dissolved solids, it pH varies greatly and it often has dissolved gases. Distilled water is nearly pure from all these things.
Dry reagent are used because they are consistantly pure. When dissolvedd in water, concentration varies (as water evaporates).
2007-03-24 05:28:29 · answer #3 · answered by Matthew P 4 · 0⤊ 0⤋
Tap water contains a lot of impurities which may bring different results.Therefore distilled water is preferred which is clean of all impurities.
2007-03-24 05:17:57 · answer #4 · answered by Gilly 2 · 0⤊ 0⤋
Tap water contains impurities which interfere with the analysis.
2007-03-24 05:00:13 · answer #5 · answered by ag_iitkgp 7 · 0⤊ 0⤋